Cyclic switching mechanism



Feb. 21, 1961 w, HAYDQN 2,972,662

CYCLIC SWITCHING MECHANISM Filed May 6, 1958 FIG; I FIG. 2

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ATTORNEYS 'CYCLIC SWITCHING MECHANISM Arthur W. Haydon, Milford, Conn., assignor to Consolidated Electronics Industries Corp., New York, N.Y., a corporation of Delaware Filed May 6, 1958, Ser. No. 733,375 Claims. (Cl. 200-38) This invention relates to repeat cycle electrical switch mechanisms and, more particularly, to a simplified assembly of a plurality of switches adapted to be actuated by associated cam means to make and break several electrical circuits sequentially.

In electrical control systems it is often necessary to incorporate apparatus which can successively open and close various circuits at unformly repetitive time intervals. Conventional apparatus for such purposes generally comprises a substantially unitary casing in which several switches are mounted with a rotating cam providing cyclical actuating means. The circuits being controlled are ordinarily electrically connected to the switch contacts by terminal members which extend through the walls of the casing to the exterior thereof. Cyclic switching apparatus of this type is adequately suited to many control systems but is oftentimes found to be too costly to warrant its incorporation into certain simpler electrical control systems where low cost and flexibility of design are important. If for some reason one of the switches enclosed in the unit is damaged, it cannot be without some inconvenience easily repaired or replaced.

The same problem is encountered when it is desired to vary the number or type of switches in the casing. Also, the cam means within the casing are not readily accessible so that they can easily be replaced to produce different cyclic switching characteristics.

In order to overcome these disadvantages and to provide an inexpensive, flexible unit, the simplified cyclic switching mechanism contemplated by the present invention was conceived. It comprises a plurality of base plates circumferentially positioned about an axis with at least one switch mounted on each base plate. Opposed end members adjoin these mounting plates substantially perpendicular to the axis and are held together by clamping means in such a manner that the base plates are maintained in position therebetween. Cam means are rotatably mounted about the axis to cyclically actuate one or more of the switches as it is rotated.

By this novel design various conventional pre-constructed switches and base plates may be employed since they are secured in the assembly simply by clamping them between the end plates. The base plates, therefore, can be of ordinary rectangular shape and need not include any special attaching means. The low cost of the assembly is due to a great extent to this manner in which a group of simple switches may be operatively positioned about a rotatable cam or cams by a simple clamping means and end plates in which the cam or cams are mounted. In addition, the design enables the entire assembly to be easily dismantled in the event it is necessary to replace either the cam means or any of the switches.

The simplicity and precision with which the switch mechanism of this invention is designed is evident in the following detailed description of a preferred embodiment nite States Patent 0 of the invention. In the drawing accompanying this description Fig. l is a top view of an embodiment of the mechanism in which four switches are operatively mounted;

Fig. 2 is a bottom view of the same;

Fig. 3 is a sectional view taken along line 3-3 of Fig. 1; and

Figs. 4 and 5 are schematic illustrations of alternate ways of incorporating additional switches into the assembly.

Referring first to Figs. 1, 2 and 3, the numerals 1t), 11, 12 and 13 indicate generally four switches mounted respectively upon rectangular dielectric base plates 14, 15, 16 and 17 in any suitable manner. For the sake of clarity in the drawings and because the particular design of these switches forms no part of the present invention, the switches are not illustrated completely. However, the respective switch actuators 18, 19, 2t] and 21 are shown and it is by depression of these actuators toward their corresponding base plates that the various circuits are opened or closed. The circuits are connected to exterior terminals which are also indicated in the drawing as, for example, at 22 and 22' on the mounting plate 15 of the switch 11. For purposes of this embodiment. it is sufficient to note that the switches 10, 11, 12 and 13 are conventional switches, perhaps of the snap-action variety, and the mounting plates 14, 15, 16 and 17 upon which these switches are mounted are conventional rectangular elements of dielectric material. A complete description of a satisfactory switch and mounting plate of this type may be found in co-pending United States ap plication Serial No. 724,036, filed March 26, 1958.

The switches and mounting plates are circumferentially arranged about an axis 25 in such a manner that each of the switch actuators 18, 19, 20 and 21 will actuate its associated switch when moved radially from the axis. Thus the mounting plates 14, 15, 16 and 17 are disposed substantially end-to-end in planes parallel to the axis 25 and are held securely in this position between supporting frame plates 26 and 27 which adjoin them above and below in planes perpendicular to the axis 25, opposed surfaces of the frame plates gripping the axial end edges of the mounting plates. The frame or end plates 26 and 27 are simple rectangular members extending beyond the circumferentially arranged switches in all directions and are urged together to hold the switches by clamping or tie means consisting of four bolts 28, 29, 30 and 31. These bolts are positioned parallel to the axis 25 and extend through corresponding holes at each corner of both end plates 26 and 27. Each bolt is threaded at both ends into conventional nuts (for example 32 and 33) above the end plate 26 and lock nuts (for example 34 and 35) below the end plate 27. By turning down these nuts, the end plates 26 and 27 are urged together to secure the switch base plates therebetween.

The bolts 28, 2?, 30 and 31 also serve to align the base plates in operative position between the end plates. As seen in Fig. l, the bolts are spaced from one another such that each base plate fits snugly between a pair of bolts, with its circumferential end edges substantially in abutting relation to the bolts, thereby preventing circumferential or tangential movement of the switches relative to the axis 25. Further aligning or locating means are provided by the end plates 26 and 27 themselves to prevent radial movement of the base plates relative to the axis 25. These additional restraining means can sist of tabs integral with the end plates and preferably stamped therefrom during fabrication of the plates. On the upper end plate 26 abutting the upper edge of the base plate 15 are four corner tabs 40, 41, 42 and 43 and four center tabs 44, 45, 46 and 47. Each corner tab abuts the inside surfaces of two adjoining base plates where they meet and thus prevent the base plates from moving inwardly relative to the axis 25. Each center tab abuts the outside edge ofone of the base plates thereby preventing outwardly movement relative to the axis. Similarly, on the lower end plate 27 restraining the lower edge of the base plates are four identical corner and end tabs, as seen in Fig. 2. The combined effect of these eight tabs and of the four bolts is such that each base plate, and therefore each switch, is held securely with a high degree of precision in operative position between the end plates 26 and 27.

Fitted coaxially with the axis 25 in apertures in the end plates 26 and 27 are journal bearings 50 and 51 rotatably supporting a shaft 52 to which cam means 53 are afiixed. The cam means 53 comprises four cams 54, 55, 56 and 57 arranged along the shaft 52 in such a manner that they cooperate with the four switch actuators 18, 19, 20 and 21 respectively. As seen in Fig. 3, the cam 55 activates the actuator 21 of the switch 13 and the cam 57 activates the actuator 14 of the switch 11. Each actuator of the four switches extends towards the axis 25 at a different level so that any one cam contacts only one actuator. Each cam has one or more shoulders on it s periphery (as shown at 58 on the cam 57) which will depress the actuator associated with the cam when the cam is rotated and its shoulder engages the actuator.

In order to actuate the switches cyclically, the cam means 53 is rotated by a pinion 60 driven by a gear 61 which is mounted upon a shaft 62 extending outwardly through and rotatably mounted in the end'plate 27. The shaft 62 is in turn driven by a suitable gear train which is driven by an electric motor 63 which may be mounted on the end plate 27.

Referring now to Fig. 4, an embodiment of the invention is illustrated which is adapted to be employed with more than four circuits. Six switch base plates 70 through 75 are arranged circumferentially about a central axis in a manner similar to that described in the previous embodiment except that they define a hexagon rather than a square. Thus the end plates which would be employed to hold the six base plates might also be of hexagonal shape. The base plates would again be secured in a generally end-to-end relation and would be held firmly in position by bolts and locating tabs.

Upon the base plates 70 through 75 are mounted switches having actuators 76 through 81 facing inwardly towards the central axis. Radially outward depression of these actuators towards their respective base plates causes actuation of the switches as described previously in reference to the first embodiment. Cam means would therefore be included to rotate about the central axis and circumferentially actuate each of the six switches. Six, rather than four, cams would be included in these cam means to effect such actuation. It will be seen, therefore, that the embodiment of Fig. 4 is substantially similar to that of Fig. 3 except that six switches are held in position by end plates about a rotating cam means rather than four switches as illustrated previously. Any reasonable number of circuits could be cyclically opened and closed in this manner simply by mounting a corresponding number of switches about a rotating cam means. Two other alternate ways of employing the invention with several additional circuits are illustrated in Fig. 5. In both these approaches, two switches are mounted on each of base plates 100, 101, 102 and 103 and the base plates are held in position by an arrangement of end plates, restraining bolts and tabs similar to those described in regard to Figs. 1, 2 and 3. The embodiments differ in that a one-piece base plate may support two switches as shown by solid lines in Fig. or, alternatively, base plates each supporting one switch may be arranged in pairs one above the other, as suggested by the broken lines. Since in either case this would involve eight switches, the cam means employed would probably include eight cams. It would be rotated in the same manner as described in the Figs. 1, 2 and 3 construction and the base plates 100, 101, 102 and 103 would be held in operative position by the same type of end plates and restraining bolts and tabs. Conceivably, arrangements of the type shown in Fig. 5 could be adapted for the control of even more circuits by increasing the number of switches around the axis in the manner set forth in reference to Fig. 4. Also, three or more switches could be supported by a one-piece base plate as shown in solid lines in Fig. 5.

It will be noted that in any of these embodiments it is possible to disassemble the unit to replace the cam means of switches simply by loosening the bolts which hold the end plates together. Moreover, when the unit is assembled, the switches are rigidly positioned with great accuracy by the various restraining means. Thus the invention contemplates an inexpensive and simple design of great precision which can be quickly adapted for different cyclic switching applications.

I claim:

1. A low-cost repeat cycle timer mechanism or the like comprising a pair of spaced frame plates, bearing means in each frame plate, a shaft journalled in said bearing means and mounting at least one cam between said frame plates, a plurality of mounting plates disposed circumferentially about said shaft and having axial end edges in abutting engagement with opposed surfaces of said frame plates, tie means engaging said frame plates and clamping said mounting plates firmly between said frame plates, locating projections on said frame plates positioning said mounting plates relative to the axis of said shaft, said tie means and said locating projections comprising the only substantial means of securing and positioning said mounting plates in said mechanism, and a switch mounted on at least one of said mounting plates and having an element positioned for engagement and actuation by said cam.

2. The mechanism of claim 1, in which said plurality of mounting plates comprises at least three such plates disposed in a substantially closed configuration and having their circumferential end edges in substantial abutment.

3. The mechanism of claim 1, in which said tie means comprises a plurality of bolts extending from one frame plate to the other, one such bolt being positioned in substantial abutment with each circumferential end edge of each mounting plate whereby said bolts serve to prevent circumferential movement of the mounting plates.

4. A low-cost repeat cycle timer mechanism or the like comprising a pair of spaced frame plates formed of stamped sheet material, bearing means in each frame plate, a shaft journaled in said bearing means and mounting at least one cam between said frame plates, a plurality of mounting plates disposed circumferentially about said shaft and having axial end edges in abutting engagement with opposed surfaces of said frame plates, tie means engaging and tending to draw together said frame plates whereby said mounting plates are clamped firmly between said frame plates, locating means on said frame plates for positioning said mounting plates relative to the axis of said shaft, said locating means being formed in substantial part by first integral tab portions projecting axially inward from said frame plates and engaging said mounting plates on one side, and second integral tab portions projecting axially inward from said frame plates and engaging said mounting plates on the other side, said tie means and said locating means comprising the only substantial means of securing and positioning said mounting plates in said mechanism, and a switch mounted on at least one of said mounting plates and having an element positioned for engagement and actuation by said cam.

5. The mechanism of claim 4 in which said mounting plates are disposed in a substantially closed configuration with their circumferential end edges in substantial abutment to form corners, said first tab portions engage the inside surfaces of said mounting plates adjacent said corners, and said second tab portions engage the outside surfaces of said plates intermediate said corners.

References Cited in the file of this patent UNITED STATES PATENTS Poole May 27, 1941 Dietrich July 15, 1952 Illian Nov. 25, 1952 Dietrich June 1, 1954 Whitlock Apr. 17, 1956 Yingst May 15, 1956 Harris Ian. 28, 1958 Jones Apr. 29, 1958 

